The subject matter of the present invention relates to a seismic signal processing method and apparatus which responds to a plurality of seismic signals emerging from an earth formation by generating either time slice attribute maps or horizon attribute maps which are used to determine the geologic features on the time slices or the horizons in the earth formation, a first said map including a plurality of quadrature correlation coefficient values, a second said map including a plurality of time lag values, and a third said map including a plurality of combined quadrature correlation coefficient/time lag values.
Two dimensional seismic data is acquired along lines that consist of geophone arrays onshore or hydrophone streamers offshore. The geophones or hydrophones act as sensors which receive seismic energy that is transmitted into an earth formation and is reflected back to the surface of the earth from the subsurface horizon interfaces in the earth formation. In three dimensional (3-D) seismic, the principle is the same except that the arrays of geophones and hydrophones are more closely spaced to provide more detailed subsurface coverage. As a result, extremely large volumes of digital data are received which needs to be recorded, stored, and processed before final interpretation can be made. The processing of the digital data requires computer resources which store and execute complex software for enhancing the digital data/seismic signals received and for muting any accompanying noise which masks the signals. Once the digital data/seismic signals are processed, the resultant processed signals are recorded and displayed in the form of horizontal time slice maps or horizon maps which display various geologic features situated on the time slice map or the horizon map in the earth formation. As a result, three dimensional seismic is used extensively to provide a more detailed structural and stratigraphic image of subsurface reservoirs. However, as good as the 3-D seismic surveys and interpreters have become, improvements are needed.
One such improvement is disclosed in U.S. Pat. No. 5,563,949 to Bahorich et al, the disclosure of which is incorporated by reference into this specification. The Bahorich patent discloses one such software based method and apparatus which, when executed by a processor of a computer, generates time slice maps that display various geologic features in the earth formation that was subjected to the seismic survey operation. However, the method and apparatus disclosed in the Bahorich patent represents one method for generating the time slice maps. Other such methods and associated apparatus can be employed for generating those time slice maps.